Immediately following harvest, growers should be getting copper spray programmes underway to help prevent Psa entering their vines through harvest wounds and leaf scars.

Incorporation of Actigard into a post-harvest programme will reduce the likelihood of disease symptoms appearing the following spring. Actigard can be tank mixed with copper and is most effective when applied to leaves that are still in good condition. Extreme care must be taken to avoid spray drift onto unharvested blocks.

Following the discovery of copper-tolerant and streptomycin-resistant Psa developing on some orchards, a robust spray programme and cutting out infected material is particulary important through autumn and winter to reduce the spread of these new Psa strains.

Best practice advice for post-harvest protection and managing tolerance and resistance:

Starting after harvest, maintain a comprehensive copper programme through autum and winter including a minimum of five copper applications at full winter rates.

Ensure water rates are sufficient for complete canopy coverage. The addition of spreaders will improve coverage.

As autumn progresses, maintain copper cover to protect fresh leaf scars. This is particularly important following the use of leaf drop sprays.

Carry out good tool hygiene between vines during winter pruning and remove infected material from orchards.

Apply coppers prior and post winter pruning.

Autumn and winter are high-risk periods for Psa-V. While vines are dormant the disease can still be active and enter through pruning wounds, new grafts and frost-damaged tissue.

Actigard manufacturer Syngenta, will not be renewing the limited label claim on soil-applied Actigard from May 2016. Therefore, from May onwards soil-applied Actigard will be considered off-label use. However, it may still be approved by Zespri under Justified Approval (JA).

Foliar-applied Actigard is not affected by this change.

Please contact Sylvia Warren, Crop Protection Advisor on spraydiary@zespri.com for more information on a JA.

Biosecurity News

21 April 2016

Strengthened border biosecurity pays off over summer

21 April 2016

Record numbers of arriving passengers into NZ over the 2015/16 summer have kept border biosecurity defences busy over the season.
However, strengthened biosecurity measures have stopped hitchhiking...

Record numbers of arriving passengers into NZ over the 2015/16 summer have kept border biosecurity defences busy over the season.

However, strengthened biosecurity measures have stopped hitchhiking pests and diseases from entering New Zealand without affecting passenger processing time. In fact, processing time is down on last year, and compliance rates (the amount of times MPI correctly detects risk goods carried by passengers) are up at 99%.

Significantly, these detections included 14 fruit fly found on passengers—reflecting the biosecurity risk pressure at our borders.